a) Field of the Invention
This invention relates to a sprag-type one-way clutch, which is adapted to be mounted between a driving shaft and a driven shaft in an automotive vehicle, general industrial equipment or the like so that motive power of rotation of the driving shaft, said rotation being only in one direction, can be transmitted to the driven shaft.
b) Description of the Related Art
A sprag-type one-way clutch is mounted between a driving shaft and a driven shaft and by way of sprags arranged between an outer ring and an inner ring, transmits rotational force of one direction from the driving shaft to the driven shaft.
When the rotational force of the one direction is applied from the driving shaft to the sprags, the sprags are wedged between the outer ring and the inner ring so that torque is transmitted to the driven shaft. Upon application of rotational force of an opposite direction, however, the sprags remain unwedged between the outer ring and the inner ring so that no transmission of torque takes place between the driving shaft and the driven shaft.
FIGS. 6 and 7 illustrate one example of such clutches.
A one-way clutch 40 is provided with plural sprags 43, which are to be wedged between an outer ring 41 and an inner ring 42, and also with a retainer 45 which is disposed between the outer ring 41 and the inner ring 42 and holds the sprags 43 in place.
The retainer 45 is constructed of a cylindrical part 48, through which sprag windows 44 are formed for retaining the sprags 43 (see FIG. 7), and a flange 47 which is formed in an elliptic or oval shape having a short-diameter portion and a long-diameter portion B (see FIG. 6).
A ring-shaped spring 46 has been mounted before-hand on the cylindrical part 48 of the retainer 45. When the sprags 43 are inserted in the sprag windows 44 of the cylindrical part 48 and the spring 46 is then fitted in spring-receiving slots formed on the respective sprags 43, the sprags 43 are retained in the corresponding sprag windows 44 under pressing force of the spring 46.
As a result, the plural sprags 43 are arranged on the retainer 45 so that the one-way clutch 40 is constructed.
Subsequent to the arrangement of the plural sprags 43 on the retainer 45, the one-way clutch 40 is mounted between the outer ring 41 and the inner ring 42 so that the inner ring 42 is located on an inner side of the retainer 45 and the outer ring 41 is positioned on an outer side of the retainer 45.
Upon mounting the clutch 40, the flange 47 of the retainer 45 is brought into contact under pressure with a circular counterbore 50 formed on a side wall of the outer ring 41. As the flange 47 is formed in the elliptic or oval shape having the short-diameter portion and the long-diameter portion B, the long-diameter portion B of the flange 47 is press-fitted in the counterbore 50, whereby the outer ring 42 and the one-way clutch 40 are fixed together.
The mounting of the one-way clutch 40 is feasible only when the counterbore 50 is formed on the side wall of the outer ring 41, and moreover, nothing is arranged or formed to restrain the thus-mounted one-way clutch 40 relative to an axial direction. Accordingly, an additional member is required to restrain the one-way clutch 40 relative to the axial direction.
Further, the clutch 40 must always be inserted through a mounting opening from the side of the cylindrical part 48 which is smaller in diameter. A limitation is therefore imposed without exception on the working direction of the one-way clutch 40 so mounted.